Cannot leave nether (vanilla minecraft snapshot 20w13a)

Dear sir/madame

I am writing to inform you on an issue I have with minecraft.

I cannot leave my nether, I cannot type commands,

and I fall forever in the void until my Y is ten million blocks down and I die and I respawn in the

nether.

It is kind of buggy too (you can't go through nether portals,

lava dosn't flow,

minecarts can't be placed,

when you create a nether portal you can break the inside of it and it will stay there without breaking the inside of the portal). 

I thried deleting my nether but it didn't work.

It is a loved world for me and I build loads of stuff in it so   p l e a s e  f i x  it  soon.

Seed (If that could help you :-] ) : -675777202518733150

Thank you in advance for your help.

Alexandros